Question 255: Properties of Matter

Question

A steel rod has a radius of $$20 \mathrm{~mm}$$ and a length of $$2.0 \mathrm{~m}$$. A force of $$62.8 ~\mathrm{kN}$$ stretches it along its length. Young's modulus of steel is $$2.0 	imes 10^{11} \mathrm{~N} / \mathrm{m}^{2}$$. The longitudinal strain produced in the wire is _____________ $$	imes 10^{-5}$$

Accepted Answer

$$
\begin{aligned}
& 	ext { Strain }=\frac{	ext { stress }}{Y}=\frac{\frac{62.8 	imes 10^3}{\pi 	imes(0.02)^2}}{2 	imes 10^{11}} \\
& =\frac{62.8 	imes 10^3}{3.14 	imes 4 	imes 10^{-4} 	imes 2 	imes 10^{11}} \\
& =2.5 	imes 10^{-4} \\
& =25 	imes 10^{-5}
\end{aligned}
$$

Properties of Matter

A steel rod has a radius of $20 \mathrm{~mm} and a length of 2.0 \mathrm{~m}. A force of 62.8 ~\mathrm{kN} stretches it along its length. Young's modulus of steel is 2.0 \times 10^{11} \mathrm{~N} / \mathrm{m}^{2}. The longitudinal strain produced in the wire is _____________ \times 10^{-5}

Choose the correct answer: